Is this the right MAF? (pix)

[9sec240]

I just bought a non running 91 hatch with a redtop swap in it. I noticed right away that there were two issues with it. The vacuum lines were AFU and the metal IAC feed tube was capped off and not run to the cold side pipe. I straightend those issues out this morning and proceded to check everything else out.

Compression test good.Getting spark.Getting injector PW.Fuel pressure good.CAS positioned correctly.

It took a long time but I did get it to fire and run. Got the timing set to 15° with TPS unplugged.

Here is the issue I am having. Its not running right. It will idle all day long but has issues reving up and driving. It just falls flat at higher rpms when free reving and wont accelrate well when driving. Black smoke out the exhaust when trying to make boost while driving.

I am curious if the MAF sensor is correct for the SR. Please take a peak and let me know if this one is correct.

[srpowered240sx]

mines not quite the same number. 2258052f00. granted, i just read it and rain back inside trying to remember.

[srpowered240sx]

id investigate that plug/harness set up to the maf. it doesnt look too hot.

[9sec240]

sombody sure ramshackled the maf plug. I did untape the wires and they are hooked up color for color. Black/white, black, and white IIRC.

The plug looks decent. I notice a difference in the way it runs when I unplug it. When I rev it, it hits a kind of two step with the MAF unplugged.

[srpowered240sx]

got any friends with a maf you can try to borrow??

[9sec240]

I have a person looking to see if he has one. He said a SOHC MAF can be used. Is that correct?

[srpowered240sx]

absolutely correct. in fact, mine is off a sohc. might be the number difference.

[Mistaken]

If he doesnt have one i can stop by AMS on monday with the one off my SR if you want to try it.

[9sec240]

If you dont mind... That sure would rule out the MAF.

You can also take a quick peek at the car and maybe see something that isnt right. I just dont know the SR all that well.

[wa-chiss]

That IS a SOHC maf and you CANNOT use one if you have a factory ecu. Don't ask me why but you just can't. Just get a maf from an SR

[Mistaken]

What time are you guys open till on monday? I have to drive from norridge to crystal lake to pick up some seats for my s13. If not i could always come out wednesday if you don't mind waiting.

[9sec240]

We will be there till 7pm tomorrow. Wednesday would work well too. We are usually there till around 11pm on Wed nights.

Thanks again for your help.

[srpowered240sx]

That IS a SOHC maf and you CANNOT use one if you have a factory ecu. Don't ask me why but you just can't. Just get a maf from an SR

bullshirt, i am using a maf of a 90 ka24e, on my stock sr ecu. try not to spread misinformation. i used the stock sr maf until i killed it running blow through, got a sohc maf and has been working beautifully for over a year. i even have another stock sr maf too, just dont want to swap plugs again for no reason.

[Blown240sx]

Ivan if you need some help with the SR you can hit me up on AIM. ChrisWKU03

The SOHC MAF will work fine the difference is you need the pigtail to make it work since the plugs are different.

We actually got a DOHC to work on my buddies SR... Dont know how but we did.

[wa-chiss]

bullshirt, i am using a maf of a 90 ka24e, on my stock sr ecu. try not to spread misinformation. i used the stock sr maf until i killed it running blow through, got a sohc maf and has been working beautifully for over a year. i even have another stock sr maf too, just dont want to swap plugs again for no reason.

Maybe it's the DOHC I'm thinking of. That was just hearsay anyway.

[Blown240sx]

Maybe it's the DOHC I'm thinking of. That was just hearsay anyway.

Then why try to post it like its a fact? Most people who report hear say would say " I heard....." not "bullshat ...."

[Mistaken]

Ill stop out around 4 tomorrow ivan. Look for the white camaro.

[ILikeMy240sx]

Doesnt sound like a MAF problem to me. You can rev high with the MAG plugged in and with it unplugged, your engine behaves differently and it limits you to around 2500~3000 RPM. So, I think your MAF is working.

Boost leak somewhere? Or timing is slightly off? Did you run the codes on your ECU?

[9sec240]

I knew the MAF was doing "something" just not sure if it was the correct one.I tried a known good SR MAF and it reacted the same way.

[9sec240]

I knew the MAF was doing "something" I was just not sure if it was the correct one. I tried a known good SR MAF and it reacted the same way so I am going to look elsewhere.

You bring up a good point about checking codes. I was going to wire up the consult port and after you mentioned the codes, that reminded me about the switch on the ECU. I will have some time tomorrow to get into the car some more. Check the wiring out and pull codes.

Thanks for the tip.

Mistaken, Thanks again for the offer on the MAF but I got that checked. Your more than welcome to come out and check out the car and maybe point me in the right direction if you have the time.

Thanks again

[mksue3240sx]

Does it show boost on the gauge?

[ILikeMy240sx]

yeah.. let us know what the ECU says...

[blackslide]

so it doesn't sound like the maf what else could it be cause my car is haveing the same problem and the z32 maf is suppose to be here today.

[Mistaken]

Sorry i couldnt of been of more help to you. If you cant figure out the problem, ill be more than happy to stop by and help out with it.

[9sec240]

OK.. so here is the latest.....

After work today, I pulled the codes and the only code stored was 12 (MAF). While I was at the ECU, I found the brown plug from the ECU not plugged into the body harness and when I went to plug that in, I found the blue plug next to it also unplugged. I plugged both in and tried to start the car. It fired right up and idled but would not take any throttle. It would choke itself out. I couldnt even pull it into the shop under its own power.

Once in the shop, I decided to tighten the RFL BOV up so it wouldnt open so easy. I removed the spring and stretched it about 2" and replaced it. I then removed the MAF to see if it needed to be cleaned. It was spotless everywhere. I grabbed another known good SR MAF and gave plugged it in and it seemed to run better and would actually respond to throttle.

I decided to try swapping the plastic electrical box off the original MAF onto the known good MAF housing and it still ran great. I swapped the two MAFs and with the original MAF body with the known good MAF electrics ran like crap.

I decided to remove the filter adapter which seemed to be partially in the airflow stream to the small hole in the MAF and that did the trick. I put everything back to stock but without the filter adapter and it rand pretty well.

I set the timing once again, did another boost leak test (passed with flying colors) and took it for a spin around the lot. It kind of laid over under boost and just didnt feel right. I decided to remove the BKR7E plugs and put the original Denso Iridium plugs in. I also advanced the timing slightly.

This was the ticket. She finally pulled clean to redline (or what I think redline might be due to no tach) There is just a slight misfire just after it spools up and then its good from there.

Its time to change the oil, get a full tank of 93 in it, get a wideband O2 sensor in it and strap it to the dyno.

So, a couple of questions if you guys dont mind.

What oil filter does this take?

If I set the timing to 15 degrees with the TPS unplugged, how come it ran better with a bit more timing? Idle jumped up a bit when I unplugged the TPS to set the timing... Is that the issue? Anybody got a shot of where the CPS is clocked to?

How much boost is it supposed to run stock? Its making less than .5 bar. How much boost CAN I run? (Stock everything but front mount, DP and exhaust)

[9sec240]

Sorry i couldnt of been of more help to you. If you cant figure out the problem, ill be more than happy to stop by and help out with it.

Thanks again for stopping by. I am sorry you didnt see my post before you came out. I owe you one.

[blackslide]

what aboult voltage can that effect the way a maf runs

[Mistaken]

I was having the same problem with my filter adapter plate to. Could be something stuck inside your maf housing maybe? Anyone know if the a DOHC housing is the same as a sr? If so i have a spare housing/maf sitting around you can have ivan.

[ILikeMy240sx]

Oil filter is from a 91 Sentra with SR20DE. Mobil # M-103

When you check the timing and unplugged the MAF, did you rev it to like 3000 RPM three times? This will kick it into timing mode. The timing light shouldnt jump around...

CAS is clocked differently for every CAS. Ive had CAS that was clocked almost all the way to get it to 15 deg and Ive had ones that stay right in the middle.

With stock T-25 you can push it to 14 psi with a fuel pump and FMIC.

[Mistaken]

Quick question where do you hook up a timing light on these cars? Ive never timed a motor with a coil over plug setup.